An injury-ravaged Manchester United delivered a much-needed victory for manager Louis van Gaal over West Ham in what was a match of dramatic contrasts for Wayne Rooney. The new United captain opened the scoring at Old Trafford before Robin van Persie doubled the advantage. But after Diafra Sakho reduced West Ham’s arrears, Rooney invited tense late pressure on his side with a ridiculously high kick from behind on Steward Downing to earn a straight red card.

Rooney’s difficult to fathom indiscretion just before the hour mark, which also means he’ll miss the next three games and not be eligible for United again until the start of November, put a dampener on what was just the club’s second victory of the season. Rooney had played his part in a full-throttle start by Van Gaal’s men that saw them 2-0 to the good by the midway point of the first half. After Rooney expertly guided in a cross from the impressive Rafael, Van Persie finished precisely on his right foot after being set up by strike partner Radamel Falcao. But thanks to David de Gea’s flapping at a corner, West Ham struck back before the break to bring thoughts flooding back of United’s dramatic collapse to lose 5-3 against Leicester City last week.

Instead, while United’s attacking play failed to reach the heights of the King Power Stadium, their defense this time was able to hold firm. And Van Gaal will take particular delight in that, given that he was down to just one fit senior center-back. It meant he was compelled to start 19-year-old debutante Patrick McNair alongside summer signing Marco Rojo, with Luke Shaw coming in for his debut at left-back. Despite a couple of major late scares, helped by a one outstanding intervention from McNair, the unfamiliar back four survived,

It was another member of the backline who played a big part in what was, as against Leicester, an encouraging start by Manchester United. Rafael was a repeated threat surging down the right flank, not least when setting up the opening goal after just five minutes. The Brazilian’s cross was perfect for Rooney to meet it with a fine controlled finish into the far corner of the net. The same combination almost made it 2-0, but this time Rooney’s effort from Rafael’s pull back was blocked by a defensive head.

Still, it didn’t take much longer for the hosts’ lead to be doubled. On-loan Barcelona midfielder Alex Song was caught dawdling on the ball inside his own half by Ander Herrera and in no time Falcao had played it through for Van Persie, who took it down the outside of Winston Reid and beat Adrian with his wrong foot.

While United had their obvious injury problems, West Ham were also missing a couple of key players. Both new signing Cheikhou Kouyate and Mark Noble were missing from the midfield which played such a big part in a superb display to beat Liverpool 3-1 a week ago. Still, West Ham did have their new forward duo intact, and, after an unintended assist from Enner Valencia, Sakho got his fourth goal in as many starts to quell United’s momentum.

De Gea has arguably been United’s most consistent player while all else has been crumbling around him in the last 13 months, but he was badly at fault this time. The Spaniard came racing out but failed to get to a corner and, after Valencia headed against the crossbar, Sakho was able to head into an unguarded net from close range.

With United now not posing the same attacking threat and a save form Adrian continuing to prevent Falcao from getting off the mark for his new club, Sakho had chances to add to his tally and bring the visitors level. But De Gea was up to the challenge to block a close-range volley behind early in the second half and then soon after, from another inviting Aaron Cresswell cross, the Senegalese striker headed into the side netting.

By that point, West Ham held a numerical advantage. Rooney has largely eradicated the explosive frustration of his youth from boiling over in recent years, but just six matches into his reign as captain, it was back in full force. Only Rooney can explain why he decided to aim a knee-high kick at Downing after the West Ham man burst past him in the middle of the pitch. What isn’t in doubt is that Lee Mason was fully justified in bringing out the red card. It would have been the last thing van Gaal wanted as he anxiously hoped for his defense to hold out. But hold out they did, thanks to a wonderful goal-saving header from McNair and an offside flag, just about, being correctly raised to deny Kevin Nolan a late equalizing goal.